Just DHT-timeout

[gdampf]

Trying with current esp-idf (End Feb. 2018), this code is not running as expected. Output produced:
=== Reading DHT ===␍␊
[08:13:21:124] DHT: Sensor Timeout␍␊
[08:13:21:124] ␍␊
[08:13:21:124] Hum 0.0␍␊
[08:13:21:124] Tmp 0.0

Sensor is connected to GPIO15, working well with Arduino-Library, but not with this one. Only adaption made: Change DHT_main.c:23 into "setDHTgpio( 15 );".

[gosouth]

Sorry, I'm very outdated, I need to remember what I did...

What version of ESP-IDF are you using? I used ESP-IDF v2.1. I think CPU Crystal frequency changed, so timing returning in getSignalLevel () may be different. I don't like this logic. It needs some interrupt blocking / priority to ensure it runs in realtime.

[suryamurugan]

Just check if your sensor is connected properly ! I got the same error when i disconnected the sensor. check(Screenshot) them before and after disconnecting the sensor .

Connected :

Disconnected :

[tinkerer2a]

I had similar issues, using an ESP32-CAM module. Got it solved by making sure the pin I was using was correctly configured as gpio by calling "gpio_pad_select_gpio" before using the DHT-library.

[loman1978]

The problem is the time! the 1uS delay is not a real 1uS delay (verified with oscilloscope) . This means you have to "calibrate" your timing". I reviewed the rotine to read the low and high level and it works better.
I suggest also do not update the temeprature and humidity before checking the checksum! This is an error. The final values should be updated only if the checksum is verified